In Multiple Objective Linear Programming (MOLP), it is well known that efficient solution and weight are correspondent to each other. The purpose of this paper is to study relationships between efficient face and the region of weight in MOLP. It is shown that the regions of weights corresponding to two efficient extreme points are also neighbor if two efficient extreme points are neighbor each other, and that the set of the efficient solutions corresponding to the common part of weight regions is efficient face. Using the above, we present a method to find the efficient solutions corresponding to a given weight and vice versa.